For FY15, we have used multi-dimensional NMR, X-ray crystallography, site-directed mutagenesis coupled with isothermal titration calorimetry to study how nucleosomes and histones are recognized by other proteins. We have determined the crystal structure of the chromatosome and identified two different binding modes of linker histones, which have implications for the higher-order chromatin structures. In addition, we solved the structure of histone variant H2A.Z in complex with the N-terminal region of the Swr1 subunit of the SWR1 remoldeler. Our results show that Swr1 deliver the H2A.Z-H2B by a chaperone mechanism.